592 
Rotation of Crops. 
We have finally, therefore, twelve plots instead of only three. 
That is to say, each of the three differently manured plots is 
divided into four as above described, and as indicated in the 
heading of the several Tables ; and, as the same form of Table 
will, as far as possible, be adopted throughout, it is very desirable 
that a clear idea of the arrangement should be formed at the 
outset. It will be seen that under each of the three main divi- 
sions designated in the heading according to the manuring, the 
results are sub-divided, showing first the produce obtained 
where the roots were carted from the land ; and secondly, where 
they were fed (or left) upon it. Lastly, under each of these 
two conditions so far as the disposal of the turnips is concerned, 
there is again a sub-division into two — one where in the third 
year of the course the land was left fallow, and the other where 
either clover or beans was grown. 
Each year the amount of produce on each of the various 
plots is weighed ; samples of each crop are taken ; in all the 
dry substance and the mineral matter (ash), and in many the 
nitrogen, is determined ; in many cases also complete analyses 
of the ashes of the crops have been made. Lastly, determina- 
tions of the total nitrogen have been made in the surface soils, 
and in the upper layers of the sub-soils, at different periods ; 
and the nitrogen as nitric acid has also been determined to a 
considerable depth. As to the results themselves, only brief 
reference to the main indications of these various investigations 
can be made. 
Tables I., II., III., and IV. give the amounts of produce of 
the turnips, the barley, the leguminous crops, and the wheat, 
respectively, in each of the eleven years in which each was 
grown, in the eleven completed courses. Each Table is divided 
into three main divisions — the upper one giving the roots, or 
the grain, &c., as the case may be ; the middle the leaves, or 
the straw ; and the lower one the total produce — roots and 
leaves, or grain and straw, together. 
The Sivedish Turnip Crops. 
Referring to Table I., relating to the Swedish turnips, it is 
seen that in the first year, 1848, there was, both without 
manure and with superphosphate alone, much more produce 
than in any subsequent year ; showing that, at the commence- 
ment, the land was in somewhat high condition due to pre- 
vious treatment. Then, again, as already said, for the tenth 
and eleventh courses, salts of potash, soda, and magnesia, were 
used as well as superphosphate. For these reasons, the results of 
